İstanbul Sağlık ve Teknoloji Üniversitesi Kurumsal Akademik Arşivi
DSpace@İSTÜN, Üniversite mensupları tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Effects of sunflower oil biodiesel blends on diesel engine performance and emissions
(International Researcher Association, 2026) Tunçer, Erdal; Kaya, Yalçın; Akal, Dinçer
The environmental impacts and limited reserves of fossil fuels have increasingly highlighted the importance of alternative fuel sources. In this study, the effects of a sunflower oil biodiesel–diesel blend on the performance, fuel consumption, and exhaust emissions of a single-cylinder diesel engine were experimentally investigated. During the tests, pure diesel fuel (B0) and a blend containing 90% diesel and 10% sunflower biodiesel (B10) were evaluated under various load conditions. After the engine reached steady-state operating temperature, power output, fuel consumption, and exhaust emissions were measured. The findings indicate that the biodiesel blend does not adversely affect engine power and provides performance comparable to pure diesel at all load levels. While fuel consumption was similar at low and medium loads, a measurable reduction was observed at high loads when using the biodiesel blend, which is attributed to the improved combustion associated with the fuel’s higher oxygen content. Regarding exhaust emissions, the addition of biodiesel resulted in reductions in CO and HC emissions, whereas a slight increase in NOₓ emissions was observed. This increase is attributed to higher combustion temperatures and is considered manageable through appropriate emission-control strategies. In conclusion, the sunflower biodiesel blend enhances fuel efficiency while maintaining engine performance and offering environmental benefits; however, additional measures may be required to mitigate elevated NOₓ emissions.
Prospective MRI-based comparison of graft maturation after ACL reconstruction using quadriceps versus hamstring tendon autograft
(SAGE Publications, 2026) Erden, Tunay; Ağır, Muzaffer; Kayaalp, M. Enes; Toker, Berkin; Taşer, Ömer
Background: Biological graft maturation after anterior cruciate ligament (ACL) reconstruction is a prolonged and heterogeneous process that may not directly correlate with clinical recovery. Magnetic resonance imaging (MRI)–based signal intensity ratio (SIR) is widely used as an indirect marker of graft remodeling and early maturation. However, comparative data regarding MRI-based graft maturation between quadriceps tendon (QT) and hamstring tendon (HT) autografts remain limited. Purpose: To compare graft maturation between all–soft tissue QT autografts and HT autografts using quantitative MRI-based SIR at 6 and 12 months after primary all-inside ACL reconstruction in athletes. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 76 athletes undergoing primary all-inside ACL reconstruction were prospectively enrolled. QT autografts were used in 39 patients and HT autografts in 37 patients. All patients followed a standardized postoperative rehabilitation protocol and underwent 3.0-T MRI evaluation at 6 and 12 months. Graft maturation was assessed using SIR measurements obtained from standardized regions of interest along the intra-articular graft, with the posterior cruciate ligament used as reference. Interob server reliability was evaluated using intraclass correlation coefficients (ICCs). Results: Baseline patient characteristics and associated surgical procedures did not differ between groups (all P . .05). At both 6 and 12 months postoperatively, the mean SIR values were similar between QT and HT autografts (P . .05). Within-group analysis showed a significant decrease in SIR values from 6 to 12 months in both groups (P\.05), indicating progressive graft maturation. The magnitude of SIR change did not differ between groups (P . .05). Interobserver reliability was excellent, with ICC(2,1) values of 0.98 at 6 months and 0.98 at 12 months. Conclusion: Quantitative MRI-based assessment using SIR demonstrated no significant difference in graft maturation between all–soft tissue QT and HT autografts at 6 and 12 months after primary all-inside ACL reconstruction. Both graft types showed comparable MRI-based maturation profiles during the early postoperative period, supporting QT autografts as a reliable alterna tive to HT autografts in athletic populations.
Thermosonication improves the bioactive properties and in vitro bioaccessibility of broccoli juice through integrated RSM and metaheuristic optimization
(Frontiers Media S. A., 2026) Arpa Zemzemoğlu, Tuba Eda; Tokatlı Demirok, Nazan; Türkol, Melikenur; Gürfidan, Remzi; Kilim, Oğuzhan; Tokatlı, Nazlı; Yıkmış, Seydi; Mohamed Ahmed, Isam A.; Aljobair, Moneera; Yinanç, Abdullah
Broccoli juice is highly nutritious, containing phenolic compounds, chlorophyll derivatives, antioxidants, and other biologically active phytochemicals; however, conventional thermal processing may reduce their stability and bioaccessibility. The aim of this study was to analyse the impact of thermosonication on the following properties of broccoli juice: bioactivity, antioxidant capacity, phenolic profile and in vitro bioaccessibility. Thermosonication conditions were optimized using Response Surface Methodology (RSM) integrated with the Grey Wolf Optimizer (GWO) and Particle Swarm Optimization (PSO) algorithms. Broccoli juice samples were subjected to conventional pasteurization and thermosonication under different processing conditions, and total chlorophyll, ascorbic acid (AA), ferric reducing antioxidant power (FRAP), total phenolic content (TPC), and individual phenolic compounds were evaluated. Digestive stability and post-digestion bioaccessibility were also assessed using a standardized in vitro gastrointestinal digestion model. The developed quadratic models exhibited high statistical significance for TPC and FRAP responses (p < 0.001), with coefficients of determination (R²) of 0.9949 and 0.9853, respectively. The optimum thermosonication conditions were identified as 40 °C, 6.75 min, and 64.04% amplitude, under which experimentally validated FRAP and TPC values reached 12.86 mmol TE/L and 149.77 mg GAE/100 mL, respectively. HPLC-DAD analysis showed that gallic acid and naringin were the predominant phenolic compounds, and that thermosonication promoted greater phenolic retention than conventional pasteurization. In vitro digestion results demonstrated that thermosonicated broccoli juice maintained significantly higher levels of TPC, FRAP, chlorophyll, and AA throughout gastrointestinal digestion, with higher TPC recovery (30.45%) than pasteurized samples (26.22%), indicating improved post-digestion bioaccessibility of phenolic compounds. Similar improvements were observed for antioxidant capacity and chlorophyll retention. Furthermore, PSO and GWO optimization results showed strong agreement with RSM predictions, confirming the robustness of the proposed optimization strategy. Overall, thermosonication was shown to effectively and sustainably enhance the functional quality, antioxidant properties, phenolic stability, and digestive bioaccessibility of broccoli juice.
Ultra-fast liquid chromatographic determination of atomoxetine, duloxetine, paroxetine, fluoxetine and sertraline in tap water, urine, and pharmaceutical formulations using 7,7,8,8-tetracyanoquinodimethane as a derivatization reagent
(Editura Acad Romane, 2026) Önal, Cem; Ceylan, Burhan; Önal, Armağan
The widespread consumption of pharmaceuticals, including both human and veterinary drugs, has resulted in the accumulation of these substances in aquatic ecosystems, presenting significant ecological threats. Psychoactive drugs, particularly antidepressants, raise particular concern due to their direct effects on brain chemistry. The growing contamination of global water systems, especially in urban environments, underscores the increasing presence of these substances in nature. A novel analytical method using UFLC-UV was developed and validated for the quantification of Atomoxetine (ATM), Duloxetine (DLX), Paroxetine (PRX), Fluoxetine (FLX) and Sertraline (SRT) in tap water, urine, and pharmaceutical samples. This technique relies on creating a purple chromogen through a displacement reaction with TCNQ in acetonitrile, with heating at 80 °C for 20 minutes. The processed sample was then injected into a C18 column. Separation was performed using acetonitrile–water (85:15) as mobile phase at 1.0 mL/min flow rate. Detection was carried out at 567 nm. The method showed linearity in the range of 10–100 ng/mL for all compounds. The validated procedure was successfully implemented to identify these antidepressants in tap water, urine, and pharmaceutical formulations. Recovery values were found between 95.41 to 100.85%. The LOD values ranged from 1.02 to 1.98 ng/mL in all of the sample matrices.
Controlled bio-catalytic synthesis of ampyrone–vanillin macromolecules: Deciphering the transition from nano-oligomers to polymers and the limits of enzymatic stability
(Elsevier, 2026) Temizkan Özdamar, Kevser
This study reports the time-controlled biocatalytic synthesis of nanostructured macromolecules derived from heteroaromatic ampyrone and bio-based vanillin. By optimizing the reaction duration (2, 4, and 6 h) with Horseradish Peroxidase (HRP), stable nano-oligomers (NSO-1, NSO-2) and a robust polymer (nano-pores polymer/NP-P) were successfully isolated. The novelty of this work lies in the precise temporal mapping of the HRP-catalyzed process, identifying a 6 h ‘stability window’ that maximizes molecular growth (Mw = 5743 g/ mol, n ≈ 14) before the onset of enzymatic chain scission. Characterization revealed a significant reduction in the optical band gap from 2.38 eV to 1.49 eV and a morphological transition from macrocrystalline rods to nano porous matrices. These results demonstrate that temporal control in enzymatic synthesis enables fine-tuning of optoelectronic and thermal properties, positioning these sustainable hybrids as viable candidates for organic photovoltaics and smart material technologies.
